from sqlalchemy import create_engine, MetaData, Table
from .config import settings

class Database:
    def __init__(self):
        self.engine = create_engine(settings.DATABASE_URL, pool_pre_ping=True)
        self.metadata = MetaData()
        self.tasks = None
        self.queue = None
        self.chunks = None
        self._reflect_tables()

    def _reflect_tables(self):
        try:
            # 自动从数据库加载表结构
            self.tasks = Table('crawl_tasks', self.metadata, autoload_with=self.engine)
            self.queue = Table('crawl_queue', self.metadata, autoload_with=self.engine)
            self.chunks = Table('knowledge_chunks', self.metadata, autoload_with=self.engine)
        except Exception as e:
            print(f"❌ 数据库表加载失败: {e}")

db_instance = Database()